| 21. |
|
|
| 22. |
|
|
| 23. |
|
|
| 24. |
- Abbas, Abdul-Karim, 1959, et al.
(författare)
-
Persistent LTP without triggered protein synthesis.
- 2009
-
Ingår i: Neuroscience research. - : Elsevier BV. - 0168-0102. ; 63:1, s. 59-65
-
Tidskriftsartikel (refereegranskat)abstract
- Protein synthesis is believed to be involved in stabilizing synaptic plasticity. Effects lasting longer than about 2-3h are considered to require synthesis of new proteins, implying a functional separation between early (E) and late (L) components. However, the issue of constitutive vs. new protein synthesis is still unclear, especially in young animals. Here, we examined the effects of two protein synthesis inhibitors, anisomycin and emetine, on long-term-potentiation (LTP) in CA1 area of hippocampal slices from 12- to 20-day-old rats. Either drug was applied from -30 min to +30 min with respect to LTP induction, a time window previously reported to be critical. However, the LTP remained stable under the entire recording period of 4h (anisomycin), or 8h (emetine). Proper preparation of emetine solution was evidenced by the fact that, in separate experiments, prolonged treatment with emetine gradually blocked baseline responses. Although no corresponding effect was observed with anisomycin, the drug was judged to be potent by its ability to inhibit yeast growth. The ability of anisomycin to inhibit protein synthesis was further confirmed by radiolabeling experiments assessing the degree of leucine incorporation. Our data suggest that LTP up to at least 8h is not dependent on triggered protein synthesis but can be attained by utilizing proteins already available at induction time.
|
|
| 25. |
- Abbas, Abdul-Karim, 1959, et al.
(författare)
-
S-sulfo-cysteine is an endogenous amino acid in neonatal rat brain but an unlikely mediator of cysteine neurotoxicity.
- 2008
-
Ingår i: Neurochemical research. - : Springer Science and Business Media LLC. - 0364-3190 .- 1573-6903. ; 33:2, s. 301-7
-
Tidskriftsartikel (refereegranskat)abstract
- S-sulfo-cysteine (SSC) is an agonist of glutamate receptors which could be involved in cysteine-induced neurotoxicity. Here we analyzed SSC by HPLC and demonstrated that the concentration of SSC in cortex of cysteine-injected rats increased to 1.4 microM, about four times the value of control rats. The neurotoxic effect of SSC was evaluated in slice cultures of rat hippocampus and compared to NMDA and cysteine. The neurotoxicity threshold of SSC was well above the tissue concentration. Our results show that SSC increases in neonatal rat brain after cysteine injection but reaches a tissue concentration far below concentrations that induce neurotoxicity in vitro. Thus, even if all the tissue SSC after cysteine injection was extracellular it would be below the threshold for toxicity, indicating that SSC is not a main excitotoxin involved in cysteine toxicity.
|
|
| 26. |
|
|
| 27. |
- Abbas, F, et al.
(författare)
-
Surgical treatment of gingival recessions using emdogain gel: clinical procedure and case reports
- 2003
-
Ingår i: Int J Periodontics Restorative Dent. ; 23, s. 607-613
-
Tidskriftsartikel (refereegranskat)abstract
- This article describes the clinical procedure and outcome of surgical treatment of gingival recessions with the adjunctive use of Emdogain gel, an enamel matrix derivative bioactive material for periodontal reconstructive surgery. Six cases with gingival recession on maxillary canines are presented with 12 months of follow-up. Initial gingival recession averaged 4.8 mm, with a mean probing pocket depth of 2.2 mm. At the 12-month follow-up, a mean of 3.5 mm of root coverage was observed (ie, 73% root coverage, range 60% to 100%). Probing pocket depth averaged 1.7 mm, indicating a 4-mm gain of clinical attachment (range 3 to 5 mm). On a clinical level, mucogingival surgery in combination with the application of Emdogain gel results in predictable root coverage and gain of clinical attachment while maintaining shallow pockets.
|
|
| 28. |
|
|
| 29. |
- Abbas, Zareen, 1962, et al.
(författare)
-
From restricted towards realistic models of salt solutions: Corrected Debye–Hückel theory and Monte Carlo simulations
- 2007
-
Ingår i: Journal of Mathematical Fluid Mechanics. - : Elsevier BV. - 1422-6952 .- 1422-6928 .- 0378-3812. ; 260:2, s. 233-247
-
Tidskriftsartikel (refereegranskat)abstract
- The properties of bulk salt solutions over wide concentration ranges are explored by a combination of simple physical theory and Monte Carlo (MC) simulations. The corrected Debye–Hückel (CDH) theory which incorporates ion size effects in a linear response approximation is extended to yield free energy and other thermodynamic properties by integration of the chemical potential over concentration. Charging integration which is usually used to obtain an electrostatic contribution of total free energy of electrolytes is avoided in this new direct approach. MC simulations are performed with a modified Widom particle insertion method, which also provides directly the ionic activity coefficients. The validity of the CDH theory is tested by comparison with the MC simulation data for 1:1, 2:1, 2:2 and 3:1 restricted primitive model (RPM) electrolytes over a wide concentration range and at various ion sizes. Mean ionic activity and osmotic coefficients calculated by the CDH theory in RPM approximation of electrolyte are fitted to experimental data by adjusting only a mean ionic diameter. Good fits up to 1 molal (m) concentration are obtained for a large number of salt solutions. MC simulations data for unrestricted primitive model (UPM) of 1:1 and 2:1 electrolytes are also fitted to the experimental data by varying the cation radius while keeping the anion radius fixed at a crystallographic value. The success of this approach is found to be salt specific. For example good fits up to 2 and 3.5 m concentrations were obtained for LiCl and LiBr, respectively. However in the case of less dissociated salts such as NaCl and KI the experimental data could only be fitted up to one molal concentration. Possibility of extending the applicability range of the CDH theory to concentrations >2 m is explored by including a concentration dependent dielectric constant as measured in experiments. Mean ionic activity coefficients for a number of salts could successfully be fitted up to 3 m concentration by adjusting only a mean ionic diameter. Difficulties encountered in simultaneously fitting the mean ionic activity and osmotic coefficients at salt concentrations >2 m are discussed.
|
|
| 30. |
- Abbas, Zareen, 1962, et al.
(författare)
-
Monte Carlo Simulations of Salt Solutions: Exploring the Validity of Primitive Models
- 2009
-
Ingår i: Journal of Physical Chemistry B. - : American Chemical Society (ACS). - 1520-6106 .- 1520-5207. ; 113:17, s. 5905-5916
-
Tidskriftsartikel (refereegranskat)abstract
- An extensive series of Monte Carlo (MC) simulations were performed in order to explore the validity of simple primitive models of electrolyte solutions and in particular the effect of ion size asymmetry on the bulk thermodynamic properties of real salt solutions. Ionic activity and osmotic coefficients were calculated for 1:1, 2:1, and 3:1 electrolytes by using the unrestricted primitive model (UPM); i.e., ions are considered as charged hard spheres of different sizes dissolved in a dielectric continuum. Mean ionic activity and osmotic coefficients calculated by the MC simulations were fitted simultaneously to the experimental data by adjusting only the cation radius while keeping the anion radius fixed at its crystallographic value. Ionic radii were further optimized by systematically varying the cation and anion radii at a fixed sum of ionic radii. The success of this approach is found to be highly salt specific. For example, experimental data (mean ionic activity and osmotic coefficients) of salts which are usually considered as dissociated such as HCl, HBr, LiCl, LiBr, LiClO4, and KOH were successfully fitted up to 1.9, 2.5, 1.9, 3, 2.5, and 4.5 M concentrations, respectively. In the case of partially dissociated salts such as NaCl, the successful fits were only obtained in a more restricted concentration range. Consistent sets of the best fitted cation radii were obtained for acids, alkali, and alkaline earth halides. A list of recommended ionic radii is also provided. The reliability of the optimized ionic radii was further tested in simulations of the osmotic coefficients of LiCl−NaCl−KCl salt mixtures. A very good agreement between the simulated and experimental data was obtained up to ionic strength of 4.5 M.
|
|
